As much as I hate to add to the barrage of "what should I buy" posts... I am going to anyway.

I am trying to expand the Lannister Core deck and have 2x Core right now. I'd like to know experienced players thoughts on purchasing 1x copies of chapter packs being a suitable amount to build decent decks with, since most of the Lannister packs I am interested in come with only 2x20 cards instead of 3x. I hate to buy 2 packs and be stuck with 4x cards that will mostly only help one deck (with some exceptions I am sure). But even if a card did help another deck there would only be 1x for that one.

Thoughts?

There's a misunderstanding there. No chapter packs were ever released with a 20x2 distribution. The earlier CP cycles (before Brotherhood Without Banners) had a model of 10x1 plus 10x3. The only AGoT LCG product that ever came with cards x2 was the original edition of "Princes of the Sun", the Martell Deluxe expansion.

Look here to see which cards came x1 and which came x3 in the ealier CPs.

If you want to beef up Lanni, I'd recommend starting with the following CPs:

The War of the Five Kings (for Pyromancer's Cache; Jhalabar Xho and Joffrey's Guard are nice, too).

Battle of the Ruby Ford (for the Castellan and Devious Intentions)

The entire King's Landing cycle of CPs.

Note that Alchemist's Guild Hall has been errata'd, and that both the Castellan and Pyromancer's Cache are Rstricted. See the FAQ for details.

To start with, buying one of each pack is enough. Later on, you'll want multiples of some cards from KL. You'll figure out which ones. You'll either have to buy more copies of the CPs in question, or you try to find Singles. Are you based in Europe? If so, I can give you tips how to get Singles.

Depends on what type of deck are you going to build for House Lannister.

Those suggested by Ratatoskr are aimed at a Lannister classic, the so-called hyperkneel deck, which basically works out by kneeling opponent's characters.

My own Lannister deck is a Clansmen deck though, and that's aimed at military challenges. To build such a deck you would need to buy the Chapter Packs from the Brotherhood Without Banners cycle. One more CP that could be useful would be Refugees of War from the A Time Of Ravens cycle.

To acquire good plots you would also need to buy some more CPs or house dedicated expansions, but you can use the website mentioned by Ratatoskr to look for them.

As others have said, which chapter packs to buy really depend on what you're trying to do. Classic Lannister revolves around kneeling everything, and if that's what you're going for the King's Landing Cycle is a great choice. Depending on how much you want to spend, 3 copies of the core set is also not a bad purchase since you'll get 3x Lannisport Weaponsmith, 3x Lannisport Steward, 3x Enemy Informer, 3x You Killed the Wrong Dwarf, 3x Distraction, 3x Golden Tooth Mines (one of the best draw cards in the game), and 3x Sunset Seas. Not to mention a whole bunch of stuff for the other houses as well. Princes of the Sun has Arys Oakheart and the Hound. If you decide to go the shadows route Kings of the Sea has a good kingdom location (I think it's Kingdom of Shadows). And of course ravens and refugees are useful too if you get the 2 packs from the time for ravens cycle.

For Lannister, i would say 3x core set, 1x of everything in KL cycle, refugees of war, princes of the sun, kings of the sea, war of 5 kings, ancient enemies, song of summer, scattered armies,

Thank you all for spending all of my money.